Heavy-duty tool with a rotationally driven, disk-shaped hub

ABSTRACT

The invention is based on an insertable tool having a rotationally drivable, disk-shaped hub ( 10, 12 ), on which a grinding means ( 14 ) forming a cutoff disk, grinding disk, roughing disk, or abrasive disk is secured in the radially outer region.  
     It is proposed that the grinding means ( 14 ) and the hub ( 10, 12 ) are joined via joining means ( 26 ) in the manner of a positive connection at least in the direction of rotation.

BACKGROUND OF THE INVENTION

[0001] The invention is based on an insertable tool with a rotationallydrivable, disk-shaped hub according to the preamble of claim 1.

[0002] A disk-shaped insertable tool, e.g., a grinding disk or a cutoffdisk for angle grinders, are usually composed entirely of bound grindingmeans and have a center, circular recess, via which the insertable toolcan be secured on an angle grinder spindle with a clamping nut innon-positive fashion in the circumferential direction and in positivefashion in the axial direction. Insertable tools are known that have areinforcement made of sheet metal in the region of the recess, and someare known that do not have a reinforcement.

ADVANTAGES OF THE INVENTION

[0003] The invention is based on an insertable tool having arotationally drivable, disk-shaped hub on which a grinding means forminga cutoff disk, grinding disk, roughing disk, or abrasive disk is securedin the radially outer region.

[0004] It is proposed that the grinding means and the hub are joined viajoining means in positive fashion at least in the direction of rotation.An advantageous connection can be achieved via which high drive torquescan be transmitted securely from the hub to the grinding means. Inaddition to a positive connection in the direction of rotation, apositive connection in the axial direction is also feasible, e.g., bymeans of projections that are angled and/or bent at right angles. Thepositive connection can be realized with simple design means withoutadditional components with projections on the hub extending in the axialdirection and forming the joining means, which said projections gripaxially in or through the grinding means and can be advantageouslyintegrally molded on the hub in a stamping process, e.g., jointly withother recesses. An axial positive connection can take place—in the caseof thin grinding means, in particular—by outwardly or inwardly bendingintegrally molded projections or borders gripping through the grindingmeans in a cost-effective fashion when the grinding means are pressed.

[0005] It is furthermore proposed that the hub is designed with aflexural strength that changes in the radial direction. An advantageoustransition can be achieved between the grinding means and a harmoniousbending line overall can be obtained. An advantageous coherence betweenthe grinding means and the hub can be achieved and detachment can besecurely prevented when attaching the insertable tool, e.g., on aspindle of an angle grinder, and during operation. Axial forces andresultant bending torques can be securely supported via a harmoniousbending line.

[0006] A flexural strength and/or bending line can be specificallyadapted to a desired course using simple design means by the shape ofrecesses installed in the radially outer region of the hub. The flexuralstrength of the hub can be specifically weakened in individual areas.The recesses can have various shapes that appear reasonable to oneskilled in the art. The recesses can be designed as slits having auniform width and/or with a width that decreases radially inwardly incontinuous fashion or in stages, by way of which the flexural strengthdecreases radially outwardly due to the hub material that decreasesradially outwardly.

[0007] In a further embodiment of the invention it is proposed that atleast one recess has a greater width in the radially inward region thanin the radially outward region, by way of which an advantageously largefastening area is provided in the radially outer region and, in theadjacent radially inner region, a type of spring area can be obtained.The recesses are advantageously designed open in the radially outwarddirection, by way of which segments can be advantageously obtained thatcan be deflected largely independent of each other. Basically, however,the recesses could also be designed closed in the radially outwarddirection.

[0008] Instead of recesses, other design embodiments appearingreasonable to one skilled in the art are feasible for achieving acertain bending line, such as embodiments having material strengths thatincrease or decrease radially outwardly, different numbers of materiallayers, different materials with different stiffness and/or withreinforcement ribs for setting a desired bending line. Furthermore,materials are feasible that were subjected to different materialtreatments radially outwardly.

[0009] The hub is advantageously produced in cost-effective andenvironmentally-friendly fashion out of sheet metal, preferably steelsheet. The grinding means, which is often difficult to recycle, can beused up completely, and the hub can simply be recycled. Basically,however, other hub materials are feasible as well, such as plastics,ceramic materials, etc.

[0010] In a further embodiment of the invention it is proposed that thehub is covered at least partially on both sides with at least one layerof the grinding means, e.g., with a fabric layer carrying an abrasivesubstance, or fiberglass mats, etc., by way of which the connectionbetween the hub and the grinding means can be improved. A positiveconnection can be achieved in both axial directions.

[0011] A connection between the hub and the grinding means can befurther improved by jointly subjecting the grinding means and thehub—during a production process of the grinding means—to at least oneheating process, and/or by connecting the grinding means with the hubvia a bonded connection in addition to a non-positive and/or positiveconnection, e.g., via an adhesive connection in particular. The bondedconnection can be created after or during the production process of thegrinding means. If the production process of the grinding means is usedto join the hub and the grinding means, additional working steps can bespared, and a production process of the insertable tool that is morestreamlined overall can be obtained. A bonding process in particular canbe easily integrated in the production process of the grinding means,whereby other bonded connections are feasible as well, however, such assoldered and/or welded connections, etc.

[0012] The means of attaining the object according to the invention canbe used with insertable tools that are secured on the spindle via aclamping nut, and particularly advantageously with hubs that have—inaddition to a center recess—recesses for fixation via a quick-releasesystem. During installation on a spindle, any installation forces thatoccur in the axial direction can be advantageously absorbed via aharmonious bending line.

SUMMARY OF THE DRAWINGS

[0013] Further advantages result from the following description of thedrawings. Exemplary embodiments of the invention are presented in thedrawings. The drawing, the description, and the claims contain numerousfeatures in combination. One skilled in the art will advantageouslyconsider them individually as well and combine them into reasonablefurther combinations.

[0014]FIG. 1 shows a schematic illustration of an angle grinder fromabove,

[0015]FIG. 2 shows an insertable tool according to the invention,

[0016]FIG. 3 shows an enlarged drawing of a hub without the grindingmeans, from above,

[0017]FIG. 4 shows the hub in FIG. 3 in a side view, and

[0018]FIG. 5 shows an alternative to FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019]FIG. 1 shows an angle grinder 36 from above with an electric motorsupported in a housing 38 and not shown in further detail. The anglegrinder 36 is capable of being guided via a first handle 40 integratedon the side furthest away from the insertable tool and extending in thelongitudinal direction, and via a second handle 44 attached to a gearboxhousing 42 in the region of the insertable tool and extendingtransversely to the longitudinal direction.

[0020]FIG. 2 shows the insertable tool in FIG. 1 in the removed state.The insertable tool has a rotationally drivable, disk-shaped hub 10 madeof steel sheet to which a grinding means 14 forming a grinding disk isattached in the radially outward region. The grinding means 14 isessentially composed of fiberglass mats, grinding means and bindingmeans that are pressed together to form a solid disk, whereby thebinding means were set in a heating process.

[0021] The hub 10 is designed with a changing flexural strength in theradial direction, whereby the hub 10 is specifically weakened in itsradially outward region to adjust the flexural strength usingslit-shaped recesses 16. The recesses 16 are designed open in theradially outward direction, by way of which segments that can bedeflected advantageously largely independently of each other areproduced. The recesses 16 have a uniform width and project radiallyinwardly until shortly before a region in which recesses 30, 32 areinstalled to secure the insertable tool to an angle grinder spindle viaa quick-release system. A circular recess 28 is installed in the centerregion of the hub 10 to center the insertable tool.

[0022] The hub 10 is covered on both sides by at least one layer 22, 24of the grinding means 14, whereby the grinding means 14—with essentiallyits entire thickness—are located in an annular indentation on a side 48facing the angle grinder, so that the hub 10 and the grinding means 14advantageously meet in a common plane in the direction of the anglegrinder 36. If the grinding means 14 should detach from the hub 10during operation, they are still secured by the hub 10 against comingloose in the direction away from the angle grinder 36 (FIGS. 2 and 4).On a side 34 facing away from the angle grinder 36, a layer 22—formed bya fiberglass mat—of the grinding means 14 covers the hub 10 radiallyinwardly.

[0023] The grinding means 14 and the hub 10 are joined in the manner ofa positive connection via joining means 26 in the direction of rotation(FIG. 4). The joining means 26 are formed by projections integrallymolded on the hub 10 and extending in the axial direction, which saidprojections grip into and/or through the grinding means 14. Theprojections forming the joining means 26 are integrally molded with therecesses 16, 28, 30, 32 in a common stamping process.

[0024] During the production process of the grinding means 14, the hub10 and the grinding means 14 are subjected to a joint heating process,whereby a bonded connection between the grinding means 14 and the hub10—in fact, an adhesive connection—is set.

[0025] An alternative hub 12 is shown in FIG. 5. Components thatessentially remain the same are basically labelled with the samereference numerals. Moreover, the description of the exemplaryembodiment in FIGS. 2 and 3 can be referred to with regard for identicalfeatures and functions.

[0026] The hub 12 has recesses 18, 20 that are designed open in theradially outward direction and that have different widths in the radialdirection. The recesses 18 are designed in the shape of a tee and have agreater width in the radially inner region than in the radially outwardregion. In contrast, the recesses 20 are designed in the shape of a veeand have a width that decreases radially inwardly.

[0027] In FIG. 5 the recesses 18 and 20 are combined, whereby it is alsofeasible, however, to provide the recesses 18 or 20 each on just onehub.

What is claimed is:
 1. An insertable tool having a rotationallydrivable, disk-shaped hub (10, 12) on which a grinding means (14)forming a cutoff disk, grinding disk, roughing disk, or abrasive disk issecured in the radially outer region, wherein the grinding means (14)and the hub (10, 12) are joined via joining means (26) in the manner ofa positive connection at least in the direction of rotation.
 2. Theinsertable tool according to claim 1, wherein projections extending inthe axial direction and forming the joining means (26) are integrallymolded on the hub (10, 12), which said projections grip in or throughthe grinding means (14).
 3. The insertable tool according to claim 1 or2, wherein the grinding means and the hub are joined via at least onejoining means in the axial direction in the manner of a positiveconnection.
 4. The insertable tool according to one of the precedingclaims, wherein the hub (10, 12) is designed with a flexural strengththat changes in the radial direction.
 5. The insertable tool accordingto claim 4, wherein recesses (16, 18, 20) for adjusting the flexuralstrength are installed in the radially outer area of the hub (10, 12).6. The insertable tool according to claim 5, wherein at least individualrecesses (16, 18, 20) are designed open in the radially outwarddirection.
 7. The insertable tool according to claim 5 or 6, wherein atleast one recess (20) has a smaller width in the radially inner regionthan in the radially outer region.
 8. The insertable tool according toone of the claims 5 through 7, wherein at least one recess (18) has agreater width in the radially inner region than in the radially outerregion.
 9. The insertable tool according to one of the preceding claims,wherein the hub (10, 12) is formed out of sheet metal.
 10. Theinsertable tool according to one of the preceding claims, wherein thehub (10, 12) is covered on both sides with at least one layer (22, 24)of the grinding means (14).
 11. The insertable tool according to one ofthe preceding claims, wherein, in a production process of the grindingmeans (14), the grinding means (14) and the hub (10, 12) are subjectedjointly to at least one heating process.
 12. The insertable toolaccording to one of the preceding claims, wherein the grinding means(14) and the hub (10, 12) are joined via a bonded connection.
 13. Theinsertable tool according to claim 12, wherein the grinding means (14)and the hub (10, 12) are adhesively bonded.
 14. The insertable toolaccording to one of the preceding claims, wherein the hub (10, 12), inaddition to a center recess (28), has recesses (30, 32) for fixation viaa quick-release system.